mpd.py

   1 # Python MPD client library
   2 # Copyright (C) 2008  J. Alexander Treuman <jat@spatialrift.net>
   3 #
   4 # This program is free software: you can redistribute it and/or modify
   5 # it under the terms of the GNU General Public License as published by
   6 # the Free Software Foundation, either version 3 of the License, or
   7 # (at your option) any later version.
   8 #
   9 # This program is distributed in the hope that it will be useful,
  10 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 # GNU General Public License for more details.
  13 #
  14 # You should have received a copy of the GNU General Public License
  15 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 import socket
  18
  19
  20 HELLO_PREFIX = "OK MPD "
  21 ERROR_PREFIX = "ACK "
  22 SUCCESS = "OK"
  23 NEXT = "list_OK"
  24
  25
  26 class MPDError(Exception):
  27     pass
  28
  29 class ConnectionError(MPDError):
  30     pass
  31
  32 class ProtocolError(MPDError):
  33     pass
  34
  35 class CommandError(MPDError):
  36     pass
  37
  38 class CommandListError(MPDError):
  39     pass
  40
  41
  42 class _NotConnected(object):
  43     def __getattr__(self, attr):
  44         return self._dummy
  45
  46     def _dummy(*args):
  47         raise ConnectionError("Not connected")
  48
  49 class MPDClient(object):
  50     def __init__(self):
  51         self.iterate = False
  52         self._reset()
  53         self._commands = {
  54             # Status Commands
  55             "clearerror":       self._getnone,
  56             "currentsong":      self._getobject,
  57             "status":           self._getobject,
  58             "stats":            self._getobject,
  59             # Playback Option Commands
  60             "crossfade":        self._getnone,
  61             "random":           self._getnone,
  62             "repeat":           self._getnone,
  63             "setvol":           self._getnone,
  64             "volume":           self._getnone,
  65             # Playback Control Commands
  66             "next":             self._getnone,
  67             "pause":            self._getnone,
  68             "play":             self._getnone,
  69             "playid":           self._getnone,
  70             "previous":         self._getnone,
  71             "seek":             self._getnone,
  72             "seekid":           self._getnone,
  73             "stop":             self._getnone,
  74             # Playlist Commands
  75             "add":              self._getnone,
  76             "addid":            self._getitem,
  77             "clear":            self._getnone,
  78             "delete":           self._getnone,
  79             "deleteid":         self._getnone,
  80             "move":             self._getnone,
  81             "moveid":           self._getnone,
  82             "playlist":         self._getplaylist,
  83             "playlistfind":     self._getsongs,
  84             "playlistid":       self._getsongs,
  85             "playlistinfo":     self._getsongs,
  86             "playlistsearch":   self._getsongs,
  87             "plchanges":        self._getsongs,
  88             "plchangesposid":   self._getchanges,
  89             "shuffle":          self._getnone,
  90             "swap":             self._getnone,
  91             "swapid":           self._getnone,
  92             # Stored Playlist Commands
  93             "listplaylist":     self._getlist,
  94             "listplaylistinfo": self._getsongs,
  95             "load":             self._getnone,
  96             "playlistadd":      self._getnone,
  97             "playlistclear":    self._getnone,
  98             "playlistdelete":   self._getnone,
  99             "playlistmove":     self._getnone,
 100             "rename":           self._getnone,
 101             "rm":               self._getnone,
 102             "save":             self._getnone,
 103             # Database Commands
 104             "count":            self._getobject,
 105             "find":             self._getsongs,
 106             "list":             self._getlist,
 107             "listall":          self._getdatabase,
 108             "listallinfo":      self._getdatabase,
 109             "lsinfo":           self._getdatabase,
 110             "search":           self._getsongs,
 111             "update":           self._getitem,
 112             # Connection Commands
 113             "close":            None,
 114             "kill":             None,
 115             "password":         self._getnone,
 116             "ping":             self._getnone,
 117             # Audio Output Commands
 118             "disableoutput":    self._getnone,
 119             "enableoutput":     self._getnone,
 120             "outputs":          self._getoutputs,
 121             # Reflection Commands
 122             "commands":         self._getlist,
 123             "notcommands":      self._getlist,
 124             "tagtypes":         self._getlist,
 125             "urlhandlers":      self._getlist,
 126         }
 127
 128     def __getattr__(self, attr):
 129         try:
 130             retval = self._commands[attr]
 131         except KeyError:
 132             raise AttributeError("'%s' object has no attribute '%s'" %
 133                                  (self.__class__.__name__, attr))
 134         return lambda *args: self._docommand(attr, args, retval)
 135
 136     def _docommand(self, command, args, retval):
 137         if self._commandlist is not None and not callable(retval):
 138             raise CommandListError("%s not allowed in command list" % command)
 139         self._writecommand(command, args)
 140         if self._commandlist is None:
 141             if callable(retval):
 142                 return retval()
 143             return retval
 144         self._commandlist.append(retval)
 145
 146     def _writeline(self, line):
 147         self._wfile.write("%s\n" % line)
 148         self._wfile.flush()
 149
 150     def _writecommand(self, command, args=[]):
 151         parts = [command]
 152         for arg in args:
 153             parts.append('"%s"' % escape(str(arg)))
 154         self._writeline(" ".join(parts))
 155
 156     def _readline(self):
 157         line = self._rfile.readline()
 158         if not line.endswith("\n"):
 159             raise ConnectionError("Connection lost while reading line")
 160         line = line.rstrip("\n")
 161         if line.startswith(ERROR_PREFIX):
 162             error = line[len(ERROR_PREFIX):].strip()
 163             raise CommandError(error)
 164         if self._commandlist is not None:
 165             if line == NEXT:
 166                 return
 167             if line == SUCCESS:
 168                 raise ProtocolError("Got unexpected '%s'" % SUCCESS)
 169         elif line == SUCCESS:
 170             return
 171         return line
 172
 173     def _readitem(self, separator):
 174         line = self._readline()
 175         if line is None:
 176             return
 177         item = line.split(separator, 1)
 178         if len(item) < 2:
 179             raise ProtocolError("Could not parse item: '%s'" % line)
 180         return item
 181
 182     def _readitems(self, separator=": "):
 183         item = self._readitem(separator)
 184         while item:
 185             yield item
 186             item = self._readitem(separator)
 187         raise StopIteration
 188
 189     def _readlist(self):
 190         seen = None
 191         for key, value in self._readitems():
 192             if key != seen:
 193                 if seen is not None:
 194                     raise ProtocolError("Expected key '%s', got '%s'" %
 195                                         (seen, key))
 196                 seen = key
 197             yield value
 198         raise StopIteration
 199
 200     def _readplaylist(self):
 201         for key, value in self._readitems(":"):
 202             yield value
 203         raise StopIteration
 204
 205     def _readobjects(self, delimiters=[]):
 206         obj = {}
 207         for key, value in self._readitems():
 208             key = key.lower()
 209             if obj:
 210                 if key in delimiters:
 211                     yield obj
 212                     obj = {}
 213                 elif obj.has_key(key):
 214                     if not isinstance(obj[key], list):
 215                         obj[key] = [obj[key], value]
 216                     else:
 217                         obj[key].append(value)
 218                     continue
 219             obj[key] = value
 220         if obj:
 221             yield obj
 222         raise StopIteration
 223
 224     def _readcommandlist(self):
 225         for retval in self._commandlist:
 226             yield retval()
 227         self._commandlist = None
 228         self._getnone()
 229         raise StopIteration
 230
 231     def _wrapiterator(self, iterator):
 232         if not self.iterate:
 233             return list(iterator)
 234         return iterator
 235
 236     def _getnone(self):
 237         line = self._readline()
 238         if line is not None:
 239             raise ProtocolError("Got unexpected return value: '%s'" % line)
 240
 241     def _getitem(self):
 242         items = list(self._readitems())
 243         if len(items) != 1:
 244             return
 245         return items[0][1]
 246
 247     def _getlist(self):
 248         return self._wrapiterator(self._readlist())
 249
 250     def _getplaylist(self):
 251         return self._wrapiterator(self._readplaylist())
 252
 253     def _getobject(self):
 254         objs = list(self._readobjects())
 255         if not objs:
 256             return {}
 257         return objs[0]
 258
 259     def _getobjects(self, delimiters):
 260         return self._wrapiterator(self._readobjects(delimiters))
 261
 262     def _getsongs(self):
 263         return self._getobjects(["file"])
 264
 265     def _getdatabase(self):
 266         return self._getobjects(["file", "directory", "playlist"])
 267
 268     def _getoutputs(self):
 269         return self._getobjects(["outputid"])
 270
 271     def _getchanges(self):
 272         return self._getobjects(["cpos"])
 273
 274     def _getcommandlist(self):
 275         return self._wrapiterator(self._readcommandlist())
 276
 277     def _hello(self):
 278         line = self._rfile.readline()
 279         if not line.endswith("\n"):
 280             raise ConnectionError("Connection lost while reading MPD hello")
 281         line = line.rstrip("\n")
 282         if not line.startswith(HELLO_PREFIX):
 283             raise ProtocolError("Got invalid MPD hello: '%s'" % line)
 284         self.mpd_version = line[len(HELLO_PREFIX):].strip()
 285
 286     def _reset(self):
 287         self.mpd_version = None
 288         self._commandlist = None
 289         self._sock = None
 290         self._rfile = _NotConnected()
 291         self._wfile = _NotConnected()
 292
 293     def connect(self, host, port):
 294         if self._sock:
 295             raise ConnectionError("Already connected")
 296         msg = "getaddrinfo returns an empty list"
 297         try:
 298             flags = socket.AI_ADDRCONFIG
 299         except AttributeError:
 300             flags = 0
 301         for res in socket.getaddrinfo(host, port, socket.AF_UNSPEC,
 302                                       socket.SOCK_STREAM, socket.IPPROTO_TCP,
 303                                       flags):
 304             af, socktype, proto, canonname, sa = res
 305             try:
 306                 self._sock = socket.socket(af, socktype, proto)
 307                 self._sock.connect(sa)
 308             except socket.error, msg:
 309                 if self._sock:
 310                     self._sock.close()
 311                 self._sock = None
 312                 continue
 313             break
 314         if not self._sock:
 315             raise socket.error(msg)
 316         self._rfile = self._sock.makefile("rb")
 317         self._wfile = self._sock.makefile("wb")
 318         try:
 319             self._hello()
 320         except:
 321             self.disconnect()
 322             raise
 323
 324     def disconnect(self):
 325         self._rfile.close()
 326         self._wfile.close()
 327         self._sock.close()
 328         self._reset()
 329
 330     def command_list_ok_begin(self):
 331         if self._commandlist is not None:
 332             raise CommandListError("Already in command list")
 333         self._writecommand("command_list_ok_begin")
 334         self._commandlist = []
 335
 336     def command_list_end(self):
 337         if self._commandlist is None:
 338             raise CommandListError("Not in command list")
 339         self._writecommand("command_list_end")
 340         return self._getcommandlist()
 341
 342
 343 def escape(text):
 344     return text.replace("\\", "\\\\").replace('"', '\\"')
 345
 346
 347 # vim: set expandtab shiftwidth=4 softtabstop=4 textwidth=79: